{
 "version": "2026-10-20",
 "license": "Dimension sheets are written by Xem Studio from the cited sources and are free to use (CC BY 4.0, attribute 'Xem Studio'). Linked files belong to their publishers under the license shown; Xem Studio does not host them. 'license_verified: false' means the license shown is from memory or the publisher's page as last read and should be confirmed at the link before commercial use.",
 "slug": "tri-clamp-bearing-cap-3in",
 "name": "3 in end caps with a bored 608 bearing boss: shaft-seal version and blind version with three 1/4 NPT bosses",
 "kind": "hardware",
 "category": "Hardware",
 "group": "Stirling & thermoacoustic",
 "year": null,
 "question": "How do I carry a crankshaft in a sealed tri-clamp crankcase?",
 "tags": [
  "cap",
  "bearing",
  "crankcase",
  "shaft seal",
  "custom cap",
  "tri-clamp",
  "stirling",
  "long earth society"
 ],
 "aliases": [
  "tri clamp bearing cap",
  "3 inch end cap with bearing",
  "sealed crankcase tri clamp"
 ],
 "overall_mm": {
  "length": null,
  "width": null,
  "height": null
 },
 "official_cad": false,
 "xem_status": "free-files",
 "les": true,
 "free_files": 2,
 "url": "https://xemstudio.com/objects/tri-clamp-bearing-cap-3in/",
 "sheet_txt": "https://xemstudio.com/objects/tri-clamp-bearing-cap-3in/sheet.txt",
 "sheet": {
  "basis": "ISO 2852 3 in face (Ø91 flange, Ø83.5 groove); 608 and ISO 6194-1 8 × 22 × 7 sizes from their standards; 1/4 NPT per ASME B1.20.1",
  "overall_mm": {
   "length": null,
   "width": null,
   "height": null
  },
  "notes": [
   "Two 3 in end caps close the run of a 3 in tee (the crankcase) and carry the crankshaft in a 608 each. On the output side an 8 × 22 × 7 rotary shaft seal sits outboard of the bearing against the outer shoulder: the crankcase pressure pushes it onto the shoulder.",
   "The blind cap carries the crankcase's three 1/4 NPT ports: fill valve, gauge and relief valve.",
   "A plain lip seal is made for a small pressure difference; for a charged crankcase use a type its maker rates above the relief setting."
  ],
  "table": {
   "columns": [
    "part",
    "bore",
    "ports"
   ],
   "rows": [
    [
     "bearing-cap-3in-608-seal",
     "Ø22 to 35: 608 + seal, Ø12 shoulder",
     "—"
    ],
    [
     "bearing-cap-3in-608-3x-npt14",
     "Ø22 to 28: 608",
     "3 × 1/4 NPT on r 27"
    ]
   ]
  }
 },
 "sheet_text": "3 in end caps with a bored 608 bearing boss: shaft-seal version and blind version with three 1/4 NPT bosses — dimension sheet\nSource: Xem Studio, https://xemstudio.com/objects/tri-clamp-bearing-cap-3in/  (CC BY 4.0)\nBasis: ISO 2852 3 in face (Ø91 flange, Ø83.5 groove); 608 and ISO 6194-1 8 × 22 × 7 sizes from their standards; 1/4 NPT per ASME B1.20.1\nCatalog version: 2026-10-20\n\nSizes: see table below\n- Two 3 in end caps close the run of a 3 in tee (the crankcase) and carry the crankshaft in a 608 each. On the output side an 8 × 22 × 7 rotary shaft seal sits outboard of the bearing against the outer shoulder: the crankcase pressure pushes it onto the shoulder.\n- The blind cap carries the crankcase's three 1/4 NPT ports: fill valve, gauge and relief valve.\n- A plain lip seal is made for a small pressure difference; for a charged crankcase use a type its maker rates above the relief setting.\n\npart  bore  ports\nbearing-cap-3in-608-seal  Ø22 to 35: 608 + seal, Ø12 shoulder  —\nbearing-cap-3in-608-3x-npt14  Ø22 to 28: 608  3 × 1/4 NPT on r 27\n\nFiles elsewhere (not hosted by Xem Studio; license as stated by the publisher):\n- ISO (via iTeh sample): ISO 2852 clamp liners: face profile and flange / groove diameters — PDF — standard excerpt; dimensions are facts — https://cdn.standards.iteh.ai/samples/7850/eb49c396488d408c8ced3e2961d76cf3/ISO-2852-1974.pdf\n- ASME: BPE Bioprocessing Equipment (clamp fitting dimensions, tube OD and wall) — standard — ASME; dimensions are facts [verify license at link] — https://www.asme.org/codes-standards/find-codes-standards/bpe-bioprocessing-equipment\n- ASME: ASME B1.20.1 Pipe Threads, General Purpose, Inch (NPT): 1/4-18 major Ø13.72, tap drill 7/16 in (11.1), L2 10.2 — standard — ASME; dimensions are facts [verify license at link] — https://www.asme.org/codes-standards/find-codes-standards/b1-20-1-pipe-threads-general-purpose-inch\n- ISO: ISO 6194-1 Rotary shaft lip-type seals: nominal dimensions (8 × 22 × 7 is a listed size) — standard — dimensions are facts [verify license at link] — https://www.iso.org/standard/41300.html\n- Long Earth Society: Engine builds — web, video — LES site — https://longearthsociety.com/engineering/\n\nFree files (CC BY 4.0, Xem Studio; STEP + STL, 2 parts): https://xemstudio.com/files/hardware/tri-clamp-bearing-cap-3in/index.json\nAPI: https://xemstudio.com/api/geometry?object=tri-clamp-bearing-cap-3in\n",
 "sources": [
  {
   "publisher": "ISO (via iTeh sample)",
   "title": "ISO 2852 clamp liners: face profile and flange / groove diameters",
   "url": "https://cdn.standards.iteh.ai/samples/7850/eb49c396488d408c8ced3e2961d76cf3/ISO-2852-1974.pdf",
   "formats": [
    "PDF"
   ],
   "license": "standard excerpt; dimensions are facts",
   "license_verified": true,
   "hosted": false
  },
  {
   "publisher": "ASME",
   "title": "BPE Bioprocessing Equipment (clamp fitting dimensions, tube OD and wall)",
   "url": "https://www.asme.org/codes-standards/find-codes-standards/bpe-bioprocessing-equipment",
   "formats": [
    "standard"
   ],
   "license": "ASME; dimensions are facts",
   "license_verified": false,
   "hosted": false
  },
  {
   "publisher": "ASME",
   "title": "ASME B1.20.1 Pipe Threads, General Purpose, Inch (NPT): 1/4-18 major Ø13.72, tap drill 7/16 in (11.1), L2 10.2",
   "url": "https://www.asme.org/codes-standards/find-codes-standards/b1-20-1-pipe-threads-general-purpose-inch",
   "formats": [
    "standard"
   ],
   "license": "ASME; dimensions are facts",
   "license_verified": false,
   "hosted": false
  },
  {
   "publisher": "ISO",
   "title": "ISO 6194-1 Rotary shaft lip-type seals: nominal dimensions (8 × 22 × 7 is a listed size)",
   "url": "https://www.iso.org/standard/41300.html",
   "formats": [
    "standard"
   ],
   "license": "dimensions are facts",
   "license_verified": false,
   "hosted": false
  },
  {
   "publisher": "Long Earth Society",
   "title": "Engine builds",
   "url": "https://longearthsociety.com/engineering/",
   "formats": [
    "web",
    "video"
   ],
   "license": "LES site",
   "license_verified": true,
   "hosted": false
  }
 ],
 "xem": {
  "status": "free-files",
  "sheet_free": true,
  "mesh_price_usd": null,
  "step_price_usd": null,
  "tolerance_mm": null
 },
 "related": [
  "rotary-shaft-seal-8x22x7",
  "stirling-built-up-crank-webs",
  "list-tri-clamp-charged-beta"
 ],
 "fits": [],
 "dimensions": "exact (nominal, no printing tolerance)",
 "dimension_rule": "All geometry on Xem Studio is exact (nominal, true size) with no printing tolerance. Where a part meets another part, the object lists its mating features (feature, exact size, what it mates with, fit class: press, slide, run, socket, clamp or designed). Apply your process's allowance to those features only; 'designed' gaps are part of the design and stay as drawn.",
 "mating": [
  {
   "feature": "face",
   "exact": "ISO 2852 3 in (Ø91 flange, Ø83.5 groove)",
   "mates": "Type B gasket, 3 in clamp",
   "fit": "clamp",
   "files": "all"
  },
  {
   "feature": "bearing bore",
   "exact": "Ø22, 608 at z 21–28",
   "mates": "608 bearing OD",
   "fit": "press",
   "files": "all"
  },
  {
   "feature": "seal bore",
   "exact": "Ø22, z 28–35, outer shoulder Ø12",
   "mates": "8 × 22 × 7 rotary shaft seal OD",
   "fit": "press",
   "files": "bearing-cap-3in-608-seal"
  },
  {
   "feature": "port bosses",
   "exact": "3 × 1/4-18 NPT on r 27, tap drill Ø11.1 × 12",
   "mates": "fill valve, gauge, relief valve",
   "fit": "designed",
   "files": "bearing-cap-3in-608-3x"
  }
 ],
 "fit_classes": {
  "press": "stays put: pin, tube, bearing or magnet held by interference. Typical FDM: hole +0.0 to +0.1 mm on diameter.",
  "slide": "assembles by hand and is held by a grub, pinch or clamp: shaft in a hub, rod in a socket, spigot in a bore. Typical FDM: +0.2 mm.",
  "run": "turns or slides in use: pin in a link, rod through a guide. Typical FDM: +0.3 mm.",
  "socket": "large sliding fit: syringe barrel, sleeve, bobbin in a bore. Typical FDM: +0.3 mm.",
  "clamp": "split part that closes on the mating part with screws: make it at size.",
  "designed": "a gap that is part of the design (piston fit option, displacer gap, air gap): do not change."
 },
 "faq": [
  {
   "q": "Why 3 in?",
   "a": "A 36 mm stroke crank and its con-rods need more than the 47.5 mm bore of a 2 in fitting; the 3 in tee's 72.9 mm bore clears them."
  }
 ],
 "files_license": null,
 "offers": [
  {
   "file": "bearing-cap-3in-608-seal",
   "formats": [
    "step",
    "stl"
   ],
   "price_usd": 0,
   "license": "CC BY 4.0 (Xem Studio)",
   "step": "https://xemstudio.com/files/hardware/tri-clamp-bearing-cap-3in/bearing-cap-3in-608-seal.step",
   "stl": "https://xemstudio.com/files/hardware/tri-clamp-bearing-cap-3in/bearing-cap-3in-608-seal.stl",
   "note": "3 in bearing cap: ISO 2852 3 in face, body Ø76.2 to 14, boss Ø36 to 40, Ø22 bore to z 35 (608 at 21–28, 8 × 22 × 7 shaft seal at 28–35), Ø12 through the outer shoulder"
  },
  {
   "file": "bearing-cap-3in-608-3x-npt14",
   "formats": [
    "step",
    "stl"
   ],
   "price_usd": 0,
   "license": "CC BY 4.0 (Xem Studio)",
   "step": "https://xemstudio.com/files/hardware/tri-clamp-bearing-cap-3in/bearing-cap-3in-608-3x-npt14.step",
   "stl": "https://xemstudio.com/files/hardware/tri-clamp-bearing-cap-3in/bearing-cap-3in-608-3x-npt14.stl",
   "note": "3 in bearing cap, blind: Ø22 bore to z 28 (608 at 21–28), three 1/4 NPT bosses on its back on r 27 (fill, gauge, relief)"
  }
 ],
 "markdown": "https://xemstudio.com/objects/tri-clamp-bearing-cap-3in/index.md"
}